Liquid fuel pumps for internal combustion engines



Sept. 19, 1961 G. VOLOSSEVICH LIQUID FUEL PUMPS FOR INTERNAL COMBUSTIONENGINES Filed Sept. 28, 1959 .l nnn l HHHU Q 11 hump G 0 606582! zLaZz/United States Patent 3,000,318 LIQUID FUEL PUMPS FOR INTERNAL COMBUSTIONENGINES George Volossevich, London, England,'-assignor to C.A.V.Limited, Acton, London, England Filed Sept. 28, 1959, Ser. No. 842,982 2Claims. (Cl. 10338) This invention relates to liquid fuel pumps forinternal combustion engines, and of the kind comprising an injectionpump for supplying fuel to the engine, a feed pump for supplying fuel tothe injection pump, and a rotary distributor for conveying fuel from theinjection pump to each in turn of the engine cylinders, said injectionpump including a pair of plungers mounted within a diametrical bore in arotary head, and an annular stationary cam for actuating the plungers asthe head rotates.

The object of the present invention is to provide in such a fuel pumpconvenient means for varying the quantity of fuel delivered to theengine cylinders by the injection pump.

According to the invention in a liquid fuel pump of the kind specifiedadjustable means is provided between the head and the annular cam fordetermining the amount of outward movement permitted to the plungers.

More specifically a liquid fuel pump of the kind specified and accordingto the invention comprises a pair of members embracing the head andshapei to coact with the outer ends of the plungers or parts carriedthereby so as to determine the permitted outward movements of theplungers, and a fork rotatable with, and movable axially relative to thehead, said fork having inclined surfaces co-operating with complementarysurfaces on said members whereby axial movement of the fork will effecta radial setting of the members.

In the accompanying drawings FIGURE 1 is a sec. tional side view of anexample of the invention, and FIG- URE 2 is a section on the line 2-2 ofFIGURE 1 with portions of the head omitted for the purpose of clarity.

Referring to the drawings the pump comprises a body part 3 which at oneend contains a feed pump 4 of the kind comprising a rotary impellerprovided with vanes. This pump 4 has an inlet 5 and an outlet passage 6in the body part, and inlet and outlet passages may be interconnectedthrough a spring-loaded relief valve (not shown) which limits thepressure which can be generated by the pump.

At the other end of the body part 3 is a fuel injection pump comprisinga rotary cylindrical head 7 in which is formed a diametrical bore 8containing a pair of reciprocatory plungers 9 which co-operate, throughrollers 10 at their outer ends, with a surrounding annular cam 11.

The rotary parts of the feed and injection pumps which are adapted to berotated by the engine through a coaxial driving shaft 12 connected tothe head 7, are interconnected by a spindle 13 which serves as adistributor, and which may be formed as an integral part of the head. Inthe spindle 13 is formed an axial passage 14 which at one end is incommunication with the diametrical bore 8 in the head, and at anotherposition is in communication with a radial passage 15 in the spindle,which communicates (as the spindle rotates) in turn with each of aplurality of angularly spaced passages 16 in the body part leading tothe different cylinders of the engine.

The feed pump 4 is adapted to deliver fuel to an annular groove 17 inthe spindle, and thence to another passage 18 in the body part whichcommunicates in turn with each of a plurality of angularly spaced radialpas sages 19 in the spindle, these passages 19 opening into the axialpassage 14. V

In action, as the spindle and rotary pump parts rotate fuel fed to theaxial passage 14 by the feed pump is discharged to the engine cylindersin turn by the inward movements of the plungers 9 of the injection pumpunder the action of the cam 11.

The pump so far described follows known practice but in applying theinvention to such a pump, surrounding the driving shaft 12 is a sleeve20 which is movable axially against the action of a spring 21 by acentrifugal governor 22, or by manual means 23. At one end of the sleeveis a fork 24 the limbs of which extend into slots 7a in the head 7 atpositions angularly removed by from the plungers 9. The inner surfacesof these limbs are inclined and co-operate respectively withcomplementarily inclined surfaces on a pair of arcuate members 25 alsodisposed between the annular cam and the head, and embracing the latter,the members being carried in a circumferential groove 7b in the head.The opposite ends of each arcuate member engage with inclined surfacesformed on the plungers 9. Moreover, the ends of the members 25 areshaped to coact with the plungers in determining the permitted outwardmovement of the latter. To allow clearance for the tips of the members25, the rollers may be formed with circumferential grooves.

In FIGURE 1 the sleeve 20 is shown in a position into which it ismovable by the centrifugal governor 22 when the driving shaft 12 isrotated by the engine at a predetermined speed. In this position of thesleeve 20 the armate members 25 serve under the action of the fork 24 toprevent actuation of the plungers 9 by the surrounding cam 11, with theresult that no fuel is delivered by the injection pump.

When the sleeve 20 is moved axially from the position shown in FIGURE 1to the extreme left hand limit of its travel, the plungers 9 can moveoutwardly to their fullest extent with the result that the maximumquantity of fuel will be fed to the cylinders of the engine at eachinward stroke of the plungers under the action of the cam. However, asthe sleeve is moved axially from its extreme left hand position to theright against the action of the spring 21 in response to a rise inengine speed or otherwise, the action of the fork 24 on the members 25will cause the latter to move radially inwards. As a result thesemembers will prevent the plungers from moving outwards to their fullestextent, thereby shortening their strokes and reducing the quantity offuel supplied to the engine.

Having thus described my invention what I claim as new and desire tosecure by Letters Patent is:

1. Means for supplying liquid fuel to a multi-cylinder internalcombustion engine, comprising in combination an injection pump having arotary member provided with a diametrical bore, a stationary annular camsurrounding said rotary member, a pair of plungers mounted within andextending from opposite ends of said bore so as to be movable inwardlyby said cam during rotation of said rotary member, a feed pump forsupplying fuel to said bore between said plungers, a rotary distributorrigid with said rotary member and provided with passages fordistributing fuel from said injection pump to each in turn of the enginecylinders, radially adjustable members which are situated between saidrotary member and said annular cam, and which embrace opposite sides ofsaid rotary member and have end parts arranged to serve as stops forlimiting outward movements of said plungers,

and a fork rotatable with, and movable axially relative to, said rotarymember, said fork and radially adjustable members having complementaryinclined surfaces which serve by contact with each other to enable thepositions of said radially adjustable members at which said stops limitthe outward movements of said plungers to be varied by axial movement ofsaid fork.

2. -Means according to claim 1 and having in combination spring-loadedmeans acting on said fork, a centrifugal governor for imparting axialmovement to said fork against the action of said spring loaded means,and manually operable means for imparting axial movement to said forkthrough the medium of said spring-loaded means independently of saidgovernor.

References Cited in the file of this patent UNITED STATES PATENTS2,784,670 High et a1. Mar. 12, 1957 2,828,697 Roos-a Apr. 1, 19582,915,014 Morris Dec. 1, 1959 2,921,437 Svenson Jan. 19, 1960 FOREIGNPATENTS 427,910 Great Britain May 2, 1935

